This invention relates to a compound needle particularly for use in loop-forming textile machines.
Knitting machines and similar loop-forming textile machines use compound needles whose hook may be closed by a closing element. The closing element is guided and controlled in such a manner that it may move onto and away from the needle hook for securely maintaining the threads captive in the needle hook. Further, the closing element can close the hook to allow the loop to glide on its exterior (knockover step). In case the closing element is displaced further outwardly beyond the hook, the loops transferred to the closing element may be taken over by other needles (loop transfer step).
Loop-forming textile machines must form the desired loops with the highest degree of reliability. Even only sporadic operational defects immediately spoil the quality of the produced fabric to an unacceptable extent. Further, the loop formation has to occur at a high speed to ensure an acceptable output rate. The loop-forming process, despite the high speed, must not be affected, to the greatest extent possible, by operational disturbances such as changing pulling forces exerted on the thread caused, for example by the predetermined pattern, non-uniform thread thickness or other influences.
Further, the compound needles should be exposed to as little wear as possible to ensure a reliable operation over a long service period, and to keep maintenance periods and down times relatively short.
U.S. Pat No. 1,673,634 discloses a compound needle having a divided closing element. The closing element is composed of two thin, resilient sheet metal closing element parts coupled to one another. The two closing element parts are, as a unit, longitudinally displaceably mounted in a closing element slot which is provided in the needle shank and which begins in the vicinity of the needle hook. The two free terminal leg portions of the closing element projecting from the closing element slot define a funnel which receives the tip of the needle hook when the closing element has been shifted to a position in the vicinity of the needle hook. For this purpose, the two free leg portions of the closing element are slightly bent away from one another. In addition, the leg portions are constructed such that they tend to resiliently move away from one another as they emerge from the closing element slot.